1 files changed, 91 insertions, 44 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index cfe128b81a01..660eac4bf2a7 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1530,7 +1530,7 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *buff;
-	int nsize, old_factor;
+	int old_factor;
 	long limit;
 	int nlen;
 	u8 flags;
@@ -1538,9 +1538,7 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
 	if (WARN_ON(len > skb->len))
 		return -EINVAL;
 
-	nsize = skb_headlen(skb) - len;
-	if (nsize < 0)
-		nsize = 0;
+	DEBUG_NET_WARN_ON_ONCE(skb_headlen(skb));
 
 	/* tcp_sendmsg() can overshoot sk_wmem_queued by one full size skb.
 	 * We need some allowance to not penalize applications setting small
@@ -1560,7 +1558,7 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
 		return -ENOMEM;
 
 	/* Get a new skb... force flag on. */
-	buff = tcp_stream_alloc_skb(sk, nsize, gfp, true);
+	buff = tcp_stream_alloc_skb(sk, gfp, true);
 	if (!buff)
 		return -ENOMEM; /* We'll just try again later. */
 	skb_copy_decrypted(buff, skb);
@@ -1568,7 +1566,7 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
 
 	sk_wmem_queued_add(sk, buff->truesize);
 	sk_mem_charge(sk, buff->truesize);
-	nlen = skb->len - len - nsize;
+	nlen = skb->len - len;
 	buff->truesize += nlen;
 	skb->truesize -= nlen;
 
@@ -1626,13 +1624,7 @@ static int __pskb_trim_head(struct sk_buff *skb, int len)
 	struct skb_shared_info *shinfo;
 	int i, k, eat;
 
-	eat = min_t(int, len, skb_headlen(skb));
-	if (eat) {
-		__skb_pull(skb, eat);
-		len -= eat;
-		if (!len)
-			return 0;
-	}
+	DEBUG_NET_WARN_ON_ONCE(skb_headlen(skb));
 	eat = len;
 	k = 0;
 	shinfo = skb_shinfo(skb);
@@ -1671,12 +1663,10 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
 
 	TCP_SKB_CB(skb)->seq += len;
 
-	if (delta_truesize) {
-		skb->truesize	   -= delta_truesize;
-		sk_wmem_queued_add(sk, -delta_truesize);
-		if (!skb_zcopy_pure(skb))
-			sk_mem_uncharge(sk, delta_truesize);
-	}
+	skb->truesize	   -= delta_truesize;
+	sk_wmem_queued_add(sk, -delta_truesize);
+	if (!skb_zcopy_pure(skb))
+		sk_mem_uncharge(sk, delta_truesize);
 
 	/* Any change of skb->len requires recalculation of tso factor. */
 	if (tcp_skb_pcount(skb) > 1)
@@ -2126,11 +2116,9 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
 	u8 flags;
 
 	/* All of a TSO frame must be composed of paged data.  */
-	if (skb->len != skb->data_len)
-		return tcp_fragment(sk, TCP_FRAG_IN_WRITE_QUEUE,
-				    skb, len, mss_now, gfp);
+	DEBUG_NET_WARN_ON_ONCE(skb->len != skb->data_len);
 
-	buff = tcp_stream_alloc_skb(sk, 0, gfp, true);
+	buff = tcp_stream_alloc_skb(sk, gfp, true);
 	if (unlikely(!buff))
 		return -ENOMEM;
 	skb_copy_decrypted(buff, skb);
@@ -2319,6 +2307,57 @@ static bool tcp_can_coalesce_send_queue_head(struct sock *sk, int len)
 	return true;
 }
 
+static int tcp_clone_payload(struct sock *sk, struct sk_buff *to,
+			     int probe_size)
+{
+	skb_frag_t *lastfrag = NULL, *fragto = skb_shinfo(to)->frags;
+	int i, todo, len = 0, nr_frags = 0;
+	const struct sk_buff *skb;
+
+	if (!sk_wmem_schedule(sk, to->truesize + probe_size))
+		return -ENOMEM;
+
+	skb_queue_walk(&sk->sk_write_queue, skb) {
+		const skb_frag_t *fragfrom = skb_shinfo(skb)->frags;
+
+		if (skb_headlen(skb))
+			return -EINVAL;
+
+		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++, fragfrom++) {
+			if (len >= probe_size)
+				goto commit;
+			todo = min_t(int, skb_frag_size(fragfrom),
+				     probe_size - len);
+			len += todo;
+			if (lastfrag &&
+			    skb_frag_page(fragfrom) == skb_frag_page(lastfrag) &&
+			    skb_frag_off(fragfrom) == skb_frag_off(lastfrag) +
+						      skb_frag_size(lastfrag)) {
+				skb_frag_size_add(lastfrag, todo);
+				continue;
+			}
+			if (unlikely(nr_frags == MAX_SKB_FRAGS))
+				return -E2BIG;
+			skb_frag_page_copy(fragto, fragfrom);
+			skb_frag_off_copy(fragto, fragfrom);
+			skb_frag_size_set(fragto, todo);
+			nr_frags++;
+			lastfrag = fragto++;
+		}
+	}
+commit:
+	WARN_ON_ONCE(len != probe_size);
+	for (i = 0; i < nr_frags; i++)
+		skb_frag_ref(to, i);
+
+	skb_shinfo(to)->nr_frags = nr_frags;
+	to->truesize += probe_size;
+	to->len += probe_size;
+	to->data_len += probe_size;
+	__skb_header_release(to);
+	return 0;
+}
+
 /* Create a new MTU probe if we are ready.
  * MTU probe is regularly attempting to increase the path MTU by
  * deliberately sending larger packets.  This discovers routing
@@ -2395,9 +2434,15 @@ static int tcp_mtu_probe(struct sock *sk)
 		return -1;
 
 	/* We're allowed to probe.  Build it now. */
-	nskb = tcp_stream_alloc_skb(sk, probe_size, GFP_ATOMIC, false);
+	nskb = tcp_stream_alloc_skb(sk, GFP_ATOMIC, false);
 	if (!nskb)
 		return -1;
+
+	/* build the payload, and be prepared to abort if this fails. */
+	if (tcp_clone_payload(sk, nskb, probe_size)) {
+		consume_skb(nskb);
+		return -1;
+	}
 	sk_wmem_queued_add(sk, nskb->truesize);
 	sk_mem_charge(sk, nskb->truesize);
 
@@ -2415,7 +2460,6 @@ static int tcp_mtu_probe(struct sock *sk)
 	len = 0;
 	tcp_for_write_queue_from_safe(skb, next, sk) {
 		copy = min_t(int, skb->len, probe_size - len);
-		skb_copy_bits(skb, 0, skb_put(nskb, copy), copy);
 
 		if (skb->len <= copy) {
 			/* We've eaten all the data from this skb.
@@ -2431,12 +2475,8 @@ static int tcp_mtu_probe(struct sock *sk)
 		} else {
 			TCP_SKB_CB(nskb)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags &
 						   ~(TCPHDR_FIN|TCPHDR_PSH);
-			if (!skb_shinfo(skb)->nr_frags) {
-				skb_pull(skb, copy);
-			} else {
-				__pskb_trim_head(skb, copy);
-				tcp_set_skb_tso_segs(skb, mss_now);
-			}
+			__pskb_trim_head(skb, copy);
+			tcp_set_skb_tso_segs(skb, mss_now);
 			TCP_SKB_CB(skb)->seq += copy;
 		}
 
@@ -3746,8 +3786,9 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_fastopen_request *fo = tp->fastopen_req;
-	int space, err = 0;
+	struct page_frag *pfrag = sk_page_frag(sk);
 	struct sk_buff *syn_data;
+	int space, err = 0;
 
 	tp->rx_opt.mss_clamp = tp->advmss;  /* If MSS is not cached */
 	if (!tcp_fastopen_cookie_check(sk, &tp->rx_opt.mss_clamp, &fo->cookie))
@@ -3766,25 +3807,31 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
 
 	space = min_t(size_t, space, fo->size);
 
-	/* limit to order-0 allocations */
-	space = min_t(size_t, space, SKB_MAX_HEAD(MAX_TCP_HEADER));
-
-	syn_data = tcp_stream_alloc_skb(sk, space, sk->sk_allocation, false);
+	if (space &&
+	    !skb_page_frag_refill(min_t(size_t, space, PAGE_SIZE),
+				  pfrag, sk->sk_allocation))
+		goto fallback;
+	syn_data = tcp_stream_alloc_skb(sk, sk->sk_allocation, false);
 	if (!syn_data)
 		goto fallback;
 	memcpy(syn_data->cb, syn->cb, sizeof(syn->cb));
 	if (space) {
-		int copied = copy_from_iter(skb_put(syn_data, space), space,
-					    &fo->data->msg_iter);
-		if (unlikely(!copied)) {
+		space = min_t(size_t, space, pfrag->size - pfrag->offset);
+		space = tcp_wmem_schedule(sk, space);
+	}
+	if (space) {
+		space = copy_page_from_iter(pfrag->page, pfrag->offset,
+					    space, &fo->data->msg_iter);
+		if (unlikely(!space)) {
 			tcp_skb_tsorted_anchor_cleanup(syn_data);
 			kfree_skb(syn_data);
 			goto fallback;
 		}
-		if (copied != space) {
-			skb_trim(syn_data, copied);
-			space = copied;
-		}
+		skb_fill_page_desc(syn_data, 0, pfrag->page,
+				   pfrag->offset, space);
+		page_ref_inc(pfrag->page);
+		pfrag->offset += space;
+		skb_len_add(syn_data, space);
 		skb_zcopy_set(syn_data, fo->uarg, NULL);
 	}
 	/* No more data pending in inet_wait_for_connect() */
@@ -3849,7 +3896,7 @@ int tcp_connect(struct sock *sk)
 		return 0;
 	}
 
-	buff = tcp_stream_alloc_skb(sk, 0, sk->sk_allocation, true);
+	buff = tcp_stream_alloc_skb(sk, sk->sk_allocation, true);
 	if (unlikely(!buff))
 		return -ENOBUFS;